1. Field of the Invention
The present invention concerns a semiconductor light emitting diode with improved current confinement.
2. Description of the Prior Art
Conventional light emitting diodes of a gallium arsenide-gallium aluminum arsenide double heterostructure type are described in an article by C. A. Burrus in Proceedings of the IEEE, February 1972, pages 231-232. Such diodes generally utilize a small area circular geometry contact electrode on the lower surface to help confine current close to a central light emitting well hole area in the upper substrate layer. Current between a large metal contact layer on the upper surface around the well hole and the small lower central contact is usually evenly distributed along straight converging paths and provides light output and optical coupling which are of less than optimum efficiency. In another known laser diode device, as described in articles by R. L. Hartman et al, in Applied Physics Letters, August 1973, pages 181-183, and by J. C. Dyment et al. in Proceedings of the IEEE, June 1972, pages 726-728, a process of proton bombardment has been used to increase the resistivity of GaAs layers to obtain a desired stripe geometry.